How do you handle the traffic? If every reader who clicks the link and runs the colab costs you 15 cents for traffic, that's got to get expensive unless you have some sort of "free traffic" deal or someone else is paying for it?
The free tier for traffic is "15GB of Data Transfer Out", after that it's 9 cents per GB. https://aws.amazon.com/s3/pricing/?nc1=h_ls (under "Data transfer"). Check your AWS bill!